1. Field of the Invention
The present invention relates to a method for displaying a character boldfaced with sub-pixel based precision, and an art related thereto.
2. Description of the Related Art
In order to display characters on a display screen, a character to be enhanced is displayed by being greater in size than the other characters. As a result, such a boldfaced character is rendered more conspicuous than the other characters.
The following describes specific implementation with reference to FIGS. 10-15 in order to provide boldfaced characters.
FIG. 10 illustrates pre-boldfaced character xe2x80x9cAxe2x80x9d. In FIG. 10, the character xe2x80x9cAxe2x80x9d is displayed at a rectangular display area that consists of seven pixel rows by nine pixel columns. This character data is defined with pixel-based precision.
FIG. 11 illustrates a boldfaced character xe2x80x9cAxe2x80x9d that is greater in size than the character xe2x80x9cAxe2x80x9d of FIG. 10 by an amount of a pixel. As evidenced by FIG. 11, the character xe2x80x9cAxe2x80x9d has a blank objectionably blacked out at a central portion thereof. As a result, it is difficult to determine whether the boldfaced character xe2x80x9cAxe2x80x9d as illustrated in FIG. 11 is xe2x80x9cAxe2x80x9d or xe2x80x9cxcex9xe2x80x9d. Therefore, the character of FIG. 11 is improper to display as a boldfaced character.
The above example shows that a character boldfaced with pixel-based precision is likely to involve character smearing. This disadvantage is particularly noticeable when any Japanese Kanji character consisting of a large number of components is boldfaced, or alternatively when a character-displaying screen is small in size with respect to characters.
There are display devices such as a color LCD, a color plasma display, and an organic EL display, in which three light-emitting elements for illuminating different colors (xe2x80x9cRxe2x80x9d or red, xe2x80x9cGxe2x80x9d or green, and xe2x80x9cBxe2x80x9d or blue) are aligned with each other in a certain direction in order to form a pixel, and further which the three light-emitting elements RGB are independently controllable.
The use of such a display device allows characters to be boldfaced on a per sub-pixel basis that is greater in fineness than a pixel-by-pixel basis. Each of the light-emitting elements corresponds to a sub-pixel.
In a character zone of FIG. 10, assume that a plurality of light-emitting elements that forms each pixel is aligned with each other in a direction of x-axis. In FIG. 10, a character line width extends in the direction of x-axis. FIG. 12 illustrates a boldfaced character that is obtained by boldfacing the character of FIG. 10 with sub-pixel based precision. This example as shown in FIG. 12 is partially described in published Japanese Patent Application Laid-Open No. 2001-100725.
In FIG. 12, a character line width of the character xe2x80x9cAxe2x80x9d is increased by illuminating a sub-pixel next to each pixel at either end thereof in the horizontal direction of the pixels. FIG. 13 illustrates the boldfaced character of FIG. 12 in a manner similar to the way in which FIG. 11 illustrates the boldfaced character xe2x80x9cAxe2x80x9d.
As evidenced by FIG. 13, when the character xe2x80x9cAxe2x80x9d is boldfaced with sub-pixel based precision, then a central blank of the boldfaced character xe2x80x9cAxe2x80x9d remains intact. As a result, the boldfaced character xe2x80x9cAxe2x80x9d is obviously identified as xe2x80x9cAxe2x80x9d, not xe2x80x9cxcex9xe2x80x9d.
However, the above discussion takes no account of how much the luminous intensity of each of the light-emitting elements contributes. Three primary colors (RGB) have an intensity contribution in a RGB ratio of 3:6:1. This means that there are great differences in luminous intensity between the three primary colors. More specifically, xe2x80x9cBxe2x80x9d (blue) has luminous intensity as small as one sixth of that of xe2x80x9cGxe2x80x9d (green). Accordingly, boldfacing each character only on the basis of the above discussion brings about a problem in which a character line width appears to be partially cut away, thereby producing an isolated sub-pixel spot, with a consequential poor quality display, as detailed below.
(When a Character Line Width is Increased by an Amount of a Sub-Pixel)
FIG. 14(a) illustrates three light-emitting elements serially arranged in the order of RGB, in which a B-light emitting element as depicted by an arrow looks dim in brightness when compared with the remaining light-emitting elements.
FIG. 14(b) illustrates an additional R-light emitting element positioned rightward next to the three light-emitting elements RGB. As illustrated in the drawings of the present specification, several light-emitting elements having the signs xe2x80x9c+xe2x80x9d carried thereon is identified as being additionally illuminated in order to provide a boldfaced character. As illustrated in FIG. 14(b), when the additional R-light emitting element is illuminated in order to provide the boldfaced character, then the dim B-light emitting element located adjacent to the additional R-light emitting element isolates the additional R-light emitting element from the other light-emitting elements RG. As a result, the additional R-light emitting element is objectionably an isolated sub-pixel spot when being additionally illuminated.
As illustrated in FIG. 14(c), when the three light-emitting elements are aligned with each other in the order of BGR, then they are a mirror image of the light-emitting elements as illustrated in FIGS. 14(a) and 14(b). As a result, as illustrated in FIG. 14(d), an additional R-light emitting element next to the three light-emitting elements BGR objectionably results in an isolated sub-pixel spot when being additionally illuminated.
(When a Character Line Width is Increased by Amounts of Two Sub-Pixels)
FIG. 15(a) illustrates three light-emitting elements serially arranged in the order of RGB. As illustrated in FIG. 15(b), two additional light-emitting elements xe2x80x9cGxe2x80x9d, xe2x80x9cBxe2x80x9d positioned leftward next to the three light-emitting elements RGB are illuminated in order to provide a boldfaced character. In this case, the additional B-light emitting element looks dim in brightness. As a result, the additional G-light emitting element objectionably results in an isolated sub-pixel spot when being additionally illuminated.
As illustrated in FIG. 15(c), when the three light-emitting elements are aligned with each other in the order of BGR, then they are a mirror image of the light-emitting elements of FIGS. 15(a) and 15(b). As a result, as illustrated in FIG. 15(d), an additional G-light emitting element is objectionably an isolated sub-pixel spot when being additionally illuminated.
As described above, the prior art involves the problem in which a boldfaced character has a character line width appearing to be partially broken away, thereby producing an isolated sub-pixel spot, with ensuing degradation in display quality.
In view of the above, an object of the present invention is to provide a boldfaced character-displaying method designed to display an easy-to-read boldfaced character that is provided with sub-pixel based precision without detracting from the display quality of the boldfaced character.
A first aspect of the present invention provides a boldfaced character-displaying method comprising the steps of: obtaining character data to be displayed; boldfacing the obtained character data by increasing a character line width of the obtained character data in a first direction by an amount corresponding to at least a width of a light-emitting element; and displaying a boldfaced character on a display screen of a display device in accordance with data derived from the boldfaced character data, wherein the step of boldfacing the obtained character data includes the step of selecting a character line width-increasing pattern in accordance with a degree to which the luminous intensity of the light-emitting elements contributes.
The above construction provides simple character boldfacing with sub-pixel based precision, and further inhibits isolated sub-pixel spot-caused degradation in display quality in view of how much the luminous intensity of the light-emitting elements contributes.
A second aspect of the present invention provides a boldfaced character-displaying method as defined in the first aspect of the present invention, wherein the step of boldfacing the obtained character data includes one of the steps of increasing the character line width by an amount corresponding to the width of the light-emitting element and increasing the character line width twice as large as the width of the light-emitting element.
The above construction provides a character that is boldfaced within finer limits than a per-pixel boldfaced character, and thus inhibits boldface-caused character smearing.
A third aspect of the present invention provides a boldfaced character-displaying method as defined in the first aspect of the present invention, wherein respective light-emitting elements illuminate three primary colors RGB, and are aligned with each other in one of order of RGB and that of BGR.
The above construction allows the present invention to be applied to display devices in widespread use, such as a color LCD, a plasma display, and an organic EL display.
A fourth aspect of the present invention provides a boldfaced character-displaying method as defined in the first aspect of the present invention, wherein the step of boldfacing the obtained character data includes the step of avoiding, when increasing the character line width, a pattern in which a B-light (blue) emitting element is located at a next-to-endmost inner position of the increased character line width.
The above construction eliminates an objectionable phenomenon in which a contiguously adjacent light-emitting element located outward next to the additional B-light emitting element results in an isolated sub-pixel spot.
A fifth aspect of the present invention provides a boldfaced character-displaying method as defined in the first aspect of the present invention, wherein three light-emitting elements are aligned with each other in the order of RGB to form a pixel, and wherein an additional B-light (blue) emitting element positioned leftward next to the three light-emitting elements RGB is illuminated when the character line width is increased by an amount corresponding to the width of the light-emitting element.
The above construction eliminates the occurrence of an isolated sub-pixel spot because the additional B-light (blue) emitting element is located at an endmost position of the increased character line width toward an increased portion thereof.
A sixth aspect of the present invention provides a boldfaced character-displaying method as defined in the first aspect of the present invention, wherein three light-emitting elements are aligned with each other in the order of RGB to form a pixel, and wherein additional R-light (red) and G-light (green) emitting elements positioned rightward next to the three light-emitting elements RGB are illuminated when the character line width is increased by an amount twice as large as the width of the light-emitting element.
The above construction eliminates the occurrence of an isolated sub-pixel spot at the increased character line width toward an increased portion thereof. As a result, good display quality is retained.
A seventh aspect of the present invention provides a boldfaced character-displaying method as defined in the first aspect of the present invention, wherein three light-emitting elements are aligned with each other in the order of BGR to form a pixel, and wherein an additional B-light (blue) emitting element located rightward next to the three light-emitting elements BGR is illuminated when the character line width is increased by an amount corresponding to the width of the light-emitting element.
The above construction eliminates the occurrence of an isolated sub-pixel spot because the additional B-light (blue) emitting element is located at an endmost position of the increased character line width toward an increased portion thereof.
An eighth aspect of the present invention provides a boldfaced character-displaying method as defined in the first aspect of the present invention, wherein three light-emitting elements are aligned with each other in the order of BGR to form a pixel, and wherein additional G-light (green) and R-light (red) emitting elements arranged leftward next to the three light-emitting elements BGR are illuminated when the character line width is increased by an amount twice as large as the width of the light-emitting element.
The above construction eliminates the occurrence of an isolated sub-pixel spot at the increased character line width toward an increased portion thereof. As a result, good display quality is retained.
A ninth aspect of the present invention provides a boldfaced character-displaying method as defined in the first aspect of the present invention, wherein the step of displaying a boldfaced character on a display screen includes the step of smoothing the boldfaced character data before displaying the boldfaced character on the display screen.
The above construction renders the boldfaced character easier to view.
The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings, in which like reference numerals designate the same elements.